/*
 *  Copyright 2017 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */
#ifndef RTC_BASE_REFCOUNTER_H_
#define RTC_BASE_REFCOUNTER_H_

#include "rtc_base/atomicops.h"
#include "rtc_base/refcount.h"

namespace webrtc
{
namespace webrtc_impl
{

    class RefCounter
    {
    public:
        explicit RefCounter(int ref_count)
            : ref_count_(ref_count)
        {
        }
        RefCounter() = delete;

        void IncRef() { rtc::AtomicOps::Increment(&ref_count_); }

        // TODO(nisse): Switch return type to RefCountReleaseStatus?
        // Returns true if this was the last reference, and the resource protected by
        // the reference counter can be deleted.
        rtc::RefCountReleaseStatus DecRef()
        {
            return (rtc::AtomicOps::Decrement(&ref_count_) == 0)
                ? rtc::RefCountReleaseStatus::kDroppedLastRef
                : rtc::RefCountReleaseStatus::kOtherRefsRemained;
        }

        // Return whether the reference count is one. If the reference count is used
        // in the conventional way, a reference count of 1 implies that the current
        // thread owns the reference and no other thread shares it. This call performs
        // the test for a reference count of one, and performs the memory barrier
        // needed for the owning thread to act on the resource protected by the
        // reference counter, knowing that it has exclusive access.
        bool HasOneRef() const
        {
            return rtc::AtomicOps::AcquireLoad(&ref_count_) == 1;
        }

    private:
        volatile int ref_count_;
    };

} // namespace webrtc_impl
} // namespace webrtc

#endif // RTC_BASE_REFCOUNTER_H_